The U.S. attorney's office has assigned one of its top prosecutors to assist D.C. police officials in their renewed investigation of one of the biggest multiple-slaying cases in the District.

Kathleen Voelker, recently named chief of the D.C. Superior Court's chronic offender unit, will help investigate the slayings of four people who were found shot April 9 in a Southeast Washington apartment building, sources said.

That decision was made Tuesday during a meeting between U.S. Attorney Joseph diGenova and Police Chief Maurice T. Turner Jr. who, according to one source, also agreed that the primary responsibility over the case will remain with a special D.C. police task force recently assigned to rework it.

The bodies of the four -- Carolann Resper, 26; Juanita Beasley, 22; Ronnie Best, 20, and Reginald Harris, 26 -- were found in an apartment at 2839 Robinson Place SE after Resper failed to appear to testify at a trial.

Voelker, who has a reputation as one of the best investigators in the office, will assist in "cooperative consultation in any way she can," said one source.

There has been some disagreement between the U.S. attorney's office and D.C. police over how the investigation should be conducted and who should control it. The U.S. attorney's office recently refused to certify a police request for an arrest warrant for a key suspect on the grounds of insufficient evidence.

Prosecutors offered to take the case before a grand jury, but the police department did not ask them to do so and appointed the task force. Prosecutors and some police have suggested that the grand jury, which has the power to subpoena witnesses, could help break the case.

Tuesday's meeting, which was described as conciliatory, included Deputy Chief Alfonso D. Gibson, head of the homicide unit, and Assistant Police Chief Isaac Fulwood. It followed a report in Monday's Washington Post in which some veteran investigators said the case had been bungled from the start. The case was never made a priority and the investigators were unable to capitalize on crucial leads, sources said.

Gibson has denied the allegations and said the case had been actively investigated.